The purpose of the study is to demonstrate consistent results in 3 production lots of Hib-MenAC vaccine when extemporaneously mixed with Tritanrix™-HepB and administered as a single injection, with respect to immunogenicity, safety and reactogenicity. Tritanrix™-HepB/Hiberix™ given alone and Wyeth Lederle's meningococcal C conjugate vaccine (Meningitec™), given concomitantly with Tritanrix™-HepB/Hiberix™ will be used as benchmark vaccines for all antigens except for MenA. The immunogenicity of MenA will also be evaluated.